A pathologic fracture is a fracture of a bone with preexisting structural weakness. When considering the local treatment of pathologic fractures, those resulting from disorders which cause a generalized weakness of the whole or part of the skeleton can be largely treated conservatively. And those because of localized bone destruction or weakness often require operative treatment. For ten years from 1973 to 1983, we observed and analysed 26 cases of pathologic fractures, excluding those due to osteoporosis. The results were as follows: 1. The age distribution showed an even pattern, and the male to female ratio was 58% (15 Males): 42% (11 Females). 2. The underlying etiologies were infection in 6 cases (23%), disturbance in skeletal development in 7 cases (27%), benign tumorous lesion in 10 cases (38%) and malignant tumorous lesion in 3 cases (12%). 3. The most common site was femur, 54% (14 cases). 4. Previous treatment was carried on 38% (10 cases). 5. Of the 26 cases, conservative treatment was done in 4 cases (15%) and surgical treatment was done in 22 cases (85%).